Aphelinus rhamni Hopper & Woolley, 2012

Hopper, Keith R., Woolley, James B., Hoelmer, Kim, Wu, Kongming, Qiao, Ge-Xia & Lee, Seunghwan, 2012, An identification key to species in the mali complex of Aphelinus (Hymenoptera, Chalcidoidea) with descriptions of three new species, Journal of Hymenoptera Research 26, pp. 73-96 : 79-82

Aphelinus rhamni Hopper & Woolley sp. n. Figs 15 28

Diagnosis.

Females. Head and mesosoma dark brown to black; legs with coxae dark brown to black, profemur dark grey with pale apex, mesofemur dark grey to black, metafemur white, protibia white with pale greyish base, mesotibia dark grey to black with pale base and apex, and metatibia dark grey to black with pale base; metasoma yellowish brown with base and apex yellow; antennae yellow with basal half of scape and pedicel sometimes greyish; F3 quadrate; club 2.8 times as long as broad. Males similar except scape swollen in middle, 3 × broader in middle than at distal end, with 2 or 3 volcano-shaped secretory pores; scape dark yellowish grey, pedicel pale greyish yellow; club 3.3 times as long as broad.

Description.

Female ( Figs 16, 18, 20 , 22, 24, 25, 26, 27 ).

Body length. 0.75-0.94 (Holotype 0.87 mm).

Head. ( Figs 16 , 22 ) Head 1.2 × as broad as high in frontal view, about as broad as mesosoma; frontovertex 0.4 × head width and as broad as scape length; posterior ocelli 0.5 × their diameter from eye margin, 3.0 × their diameter from one another, and 0.33 × their diameter from occipital margin; mandible with 2 acute teeth and a broad truncate surface below the teeth; antennae as in Fig. 21 with scape 4.8 longer than broad, pedicel 1.8 × as long as broad, F1 anneliform, F2 1.5 × as broad as long, F3 quadrate, club 2.8 × as long as broad and 3.3 × times longer than F3, with 4-6 longitudinal sensilla.

Mesosoma. ( Figs 18, 20 , 27 ) Mesoscutum and scutellum with fine reticulate sculpture, longest diameter of reticulations approximately twice the diameter of scutellar sensilla, interior of reticulations with fine, granulate surface (visible only in slide-mounts under high magnification); mid-lobe of mesoscutum with 2 pairs of long setae and 35-40 short setae, side lobes each with 2 long and 1 short seta; scutellum with 2 pairs of long setae, pair of scutellar sensilla directly posterior to the anterior pair of setae and slightly posterior to middle of scutellum; mesotibial spur equal in length to mesobasitarsus; metatibial spur 0.5 × metabasitarsus.

Fore wing. ( Fig. 24 ) 2.2 × as long as broad ; costal cell with 1 row of dorsal setae and two rows of ventral setae, the posterior row extending from under the proximal end of the marginal vein almost to stigma, costal cell 1.1 × as long as marginal vein; submarginal vein with 5 setae, marginal vein with 10 setae along the anterior margin; stigmal vein short with stigma rounded; delta region proximal to linea calva with one complete line of 13-15 setae and 2-6 additional setae in angle with marginal vein, linea calva with no setae at its posterior edge; wing distal to linea calva with evenly spaced, dense dorsal setae and much smaller ventral setae.

Hind wing. ( Fig. 25 )3.9 × longer than broad, marginal fringe 0.23 × wing width.

Metasoma. ( Figs 18, 20 , 26 ) 1.4 × as long as mesosoma; ovipositor inserted at middle of metasoma, slightly exerted distally, 1.3 × longer than metatibia and mesotibia; third valvulae one-third the length of ovipositor.

Color. ( Figs 16, 18, 20 ) Head and mesosoma dark brown to black; legs with coxae dark brown to black, profemur dark grey with pale apex, mesofemur dark grey to black, metafemur white, protibia white with pale greyish base, mesotibia dark grey to black with pale base and apex, and metatibia dark grey to black with pale base; metasoma yellowish brown with venter of T1 and apex yellow; antennae yellow sometimes with basal half of scape and pedicel greyish yellow; compound eyes dark burgundy and ocelli red in life, both silver-colored in dried specimens.

Male ( Figs 15, 17, 19 , 21, 23, 28 ). Similar to female except:

Body length. 0.66-0.78 mm.

Head. ( Figs 15 , 21 ) Antenna with scape swollen in center, 3.1 × as long as broad, maximum width 3 × width at distal end, with 2-3 volcano-shaped secretory pores in single line on ventral surface, pedicel 1.8 × as long as broad, F1 subquadrate, 1.1 × as broad as long, F2 shorter, 1.4 × as broad as long, F3 trapezoidal, 1.1 × longer than width at apex, 1.5 × as long as wide at base, club 3.3 × as long as broad, with 4 longitudinal sensilla.

Metasoma. 0.7 × length of mesoma

Color. ( Figs 15, 17, 19 ) Scape dark yellowish grey, pedicel pale greyish yellow, base of metasoma pale brown and with yellow region at apex smaller.

Holotype female

(card-mounted, deposited in USNM, USNM ENT 00763638). "China, Daxing (Beijing) | 39°48'N, 116°28'E | 10.ix.2005, K. Hoelmer || ex: Aphis glycines | on: Rhamnus sp. | 2005/005 || From Lab Culture | USDA-ARS-BIIRU | Newark, Delaware"

Paratypes

(USNM, TAMU, BMNH). 33 card-mounted and 6 slide-mounted females, 19 card-mounted and 3 slide-mounted males with same data as holotype. 9 card-mounted and 2 slide-mounted females, 6 card-mounted and 2 slide-mounted males: China: Daxing (Beijing), 39°48'N, 116°28'E, 10.iv.2004, W. Meikle coll., ex: Aphis glycines on Rhamnus sp., 2004/008, from lab culture, USDA-ARS-BIIRU, Newark, Delaware.

Host.

In the field, Aphis glycines is the only known host. In laboratory experiments, Aphelinus rhamni parasitizes Aphelinus glycines and closely related species in the genus Aphis , and rarely Rhopalosiphum padi L. and Schizaphis graminum .

Etymology.

This species is named for the primary host plant of the aphid species from which it was collected. The species epithet is a noun in genitive case.

Relationships.

Aphelinus campestris and Aphelinus gossypii are the closest described species to Aphelinus rhamni based on our matrix of traits ( Table 2 ). Aphelinus rhamni differs from both species in having a more elongate club and in coloration of the metatibia. Aphelinus rhamni has a much narrower host range than Aphelinus gossypii , which is reported from at least 18 species of aphids in 10 genera and two tribes, including species which Aphelinus rhamni does not parasitize in laboratory experiments.

Figures

Figures 15 - 20. Aphelinus rhamni sp. n., paratype specimens in 95 % ethanol. 15 male antennae and face 16 female antennae and face 17 male, lateral view 18 female, lateral view 19 male, ventral view 20 female, ventral view.

Figures 21 - 28. Aphelinus rhamni sp. n., slide-mounted paratypes. 21 male antenna (TAMU x 0616221) 22 female antenna (TAMU x 0616215) 23 male fore wing (TAMU x 0616217) 24 female fore wing (TAMU x 0616215) 25 female hind wing (TAMU x 0616129) 26 female metasoma (TAMU x 0616214) 27 female mesosoma (TAMU x 0616129) 28 male genitalia (TAMU x 0616217).